The present invention relates to a gas circuit breaker installed in the substation, switching station or the like, and particularly to a puffer type gas circuit breaker for reducing the arc occurring between fixed and movable contacts by means of insulating gas.
When the movable contact of the puffer type gas circuit breaker is disconnected from the fixed contact, high-temperature plasma arc occurs in-between. This makes it necessary to blow compressed insulating gas to arc to interrupt it. In this case, insulating gas is heated by arc and turned into high-temperature gas (hot gas); then it is separated into two flows to be discharged to the fixed and movable sides.
The structure of discharging hot gas in the puffer type gas circuit breaker, particularly the structure of discharging on the movable side, is disclosed in the Official Gazette of Japanese application patent laid-open publication No. Hei08-195149, for example. According to this Official Gazette, the structure of discharging gas on the movable side is designed in such a way that hot gas flowing through the hollow portion of the movable shaft is discharged almost perpendicularly toward the inner surface of the vessel from the exhaust outlet of the movable shaft through the exhaust outlet of the puffer piston.
To avoid serious deterioration of dielectric strength in the vessel due to direct blowing of hot gas onto the inner surface of the vessel, the puffer type gas circuit breaker of the above-mentioned gas discharge structure adopts the following measures: A cylindrical shield is provided between the exhaust outlet of the puffer piston and the inner surface of the vessel. Alternatively, a large-diameter vessel is used to increase the distance from the exhaust outlet of the puffer piston to the inner surface of the vessel.
There has been growing requirements for downsizing of the gas circuit breaker in recent years because of cost reduction arising from price competition, interrupted site of an electric power station, or interrupted installation area resulting from increased demands for application to the underground electric power station. The puffer type gas circuit breaker having the above-mentioned gas discharge structure, however, cannot not be downsized due to interference by the shield. Accordingly, a puffer type gas circuit breaker is required to prevent remarkable degradation of dielectric strength in the vessel even if this shield is eliminated.
The representative object of the present invention is to provide a gas circuit breaker which can interrupt a remarkable degradation of dielectric strength in the vessel caused by hot gas and which can be downsized.
The gas circuit breaker according to the present invention is characterized by having a hot gas discharge structure which is designed to ensure that the hot gas discharged by flowing through the hollow portion of the shaft, after having been separated and fed to the movable side is discharged into the inner surface of the vessel after gas temperature and velocity have been interrupted by convection of the gas.
The gas circuit breaker according to the present invention is provided with the first and second exhaust outlets whereby gas discharged into the gas exhaust chamber is dispersed and discharged into the space between the inside of the vessel and the outside of the gas exhaust chamber.
The gas circuit breaker according to the present invention has an exhaust outlet arranged in the gas exhaust chamber, and is characterized in that gas discharged from this exhaust outlet is discharged in a slanting direction into the space between the inside of the vessel and the outside of the gas exhaust chamber.
According to this hot gas discharge structure, the hot gas flowing to the insulating rod side through the hollow portion of the shaft after having been separated and fed to the movable side is discharged into the gas discharge chamber. Hot gas is transferred into the gas exhaust chamber, and the temperature and velocity are interrupted. Hot gas with the temperature and velocity interrupted flows toward the first and second exhaust outlets, and is discharged into the inner surface of the vessel. Hot gas with interrupted temperature and velocity is discharged from the first and second exhaust outlets, and, at the same time, it is possible to control the amount of the hot gas to be blown directly onto the inner surface of the vessel. This, in turn, interrupts a remarkable degradation of the dielectric strength in the vessel.
Since the exhaust outlet is arranged as described above, the distance from the exhaust outlet to the inner surface of the vessel can be increased, and the amount of the hot gas to be blown directly onto the inner surface of the vessel can be controlled. This allows a remarkable degradation of dielectric strength in the vessel to be interrupted further.